Question

10. Hydrated salts are very common. If you heat 2.374 g of CoCl2 • x H2O, and find that 1.294 g of CoCl2 remains, what is the value of x? (A) 2 (B) 3 (C) 4 (D) 5 (E) 6

Answer 1

Answer:

the correct answer is 2

Explanation:

It is because calcium oxychloride dihydrate is heated at 100°c to make calcium oxychloride hemihydrate or pop

Answer 2

The value of x in CoCl2 . xH2O is equal to 6.

• The molar mass of CoCl2 (cobalt chloride) is equal to 130 g/mole.
• Hence the number of moles of cobalt chloride present in 2.374 g of CoCl2 . xH2O is equal to 0.01 moles (1.294/130).
• The amount of water present is equal to 1.08 g. Hence, the number of moles of water is equal to 0.06 (1.08/18).
• Since, 0.01 moles of CoCl2 contains 0.06 moles of water , one mole of CoCl2 will contain 6 moles of water.
• Therefore the value of x is equal to 6.